Again to echo what's already been said - this isn't the way to test higher ISO performance. You need low light conditions (usually translating to more shadows in your histogram) to evaluate ISO performance.

Doh! I think I was having a bad calculation day earlier. I got the 3 and 2 stop differences, but added them instead of subtracting the reduction when going to lower iso... right numbers, wrong calculation. XD

Again to echo what's already been said - this isn't the way to test higher ISO performance. You need low light conditions (usually translating to more shadows in your histogram) to evaluate ISO performance.

I've also got a few questions:

- was VR turned on?- did you use a tripod?

Yes VR was on, and yes it was handheld.

I can definitly add a darker shot, I will try to do the same flower or something similar to keep it even.

I was aware that low light = worse noise, but I wasn't really thinking about how I would not use the camera.

Generally if the light is much worse I would use a lower ISO and longer shutter speed, but for the sake of testing, I will post the other scenario as well.

Thanks for the feedback so far though, glad to know what works for others.

If you shoot with iso 1600 in low light you will notice that there is more noise. I own a 450D and I find iso1600 to be unaccepable in lowlight shots. Iso800 is barely cutting it for my standard. I dont own a d90 but I have seen some good iso 800 and iso1600 comparisons and they are both very similar. Unfortunately, both still unacceptable. Fullframe is the only real way to overcome this barrier in my opinion. D3x or even 5d mk2 are both monsters in this department. The difference is almost as much as going from an Ixus to EOS in low light.

Even more simply put, the D3X is orientated to the well lit studio environment, and the D3 is the action tool, performing grandly at high ISOs. Not that the D3X can't - it's still better than any DX Nikon. Just not there with the other full framers re:noise handling.

Returning to the review - from personal experience ISO1600 on the D90 is only there for emergencies (when used properly in challenging light conditions). Images are acceptable for web at reduced sizes.

I always read about the excellent iso performance of the d90 and how they compare it to the d300,to tell u the truth,canon's iso 1600 is much cleaner than the nikon's d90!!

that's why i always wondered why they didn't push the iso in canon above that((maybe commercial purposes)).but overall there is a big difference in how both canon and nikon deal with noise.in the end it's a personal preference and though i'm not cmparing similar category cameras (450d and d90) the d90 overall controls r much better!
also with canon,for the price u can't go wrong!!